The present invention relates to a NOx removal system for use in a boiler and for reducing NOx.
As measures for NOx reduction in boilers, there have been practiced two-stage combustion, exhaust gas recirculation and the like. In the two-stage combustion, combustion air is supplied in two stages to the burner, where the fuel is burned with a smaller amount of air than necessary for complete combustion in the first stage, and the remaining amount of air necessary for complete combustion is supplied in the second stage. In the exhaust gas recirculation, on the other hand, exhaust gas generated by combustion is circulated so as to be remixed with the fuel. However, in recent years, there have been growing concerns for environmental issues, posing a demand for further reduction in NOx.